Rolling stock includes locomotives and freight cars. In general, rolling stock vehicles are equipped with handbrakes, which are brakes that can be set manually. The handbrake of a rolling stock vehicle is set and released by turning a wheel on an end of the stock. The wheel is mounted on a shaft.
Handbrakes are used, for example, when one or several vehicles have been uncoupled from a locomotive. The handbrakes are set by crew members to prevent the rolling stock from moving on the tracks.
Prior art handbrake wheels are made of metal, a design that has remained unchanged for about a century. The handbrake wheel is made of stamped steel and has a cast iron center, which center has a square opening for receiving the shaft.
One problem with the metal wheel is that a crew member can sustain a hand injury if not wearing gloves. The steel on the wheel is unfinished and offers sharp or rough edges, including burrs.
Another problem with the metal wheel is the weight. Metal wheels are heavy. As the car moves along the track, the wheel vibrates on the shaft. Because the wheel is mounted at the end of the shaft, bearings that support the shaft are subjected to wear and premature failure. Because of the heavy vibrational load, handbrake wheel manufacturers are unwilling to provide long warranties on the handbrakes.
An Australian company developed an all-plastic handbrake wheel. The wheel was monolithic, made of the same plastic throughout. However the wheel exhibited failure, cracking in the center.